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Sept. 10, 1929- w. B. VAN ARsbEL APPARATUS FOR REGULATING GAS FLOW Original Filed Nov. 10, 1921 Patented Sept. 10, 1929.

UNITED STATES PATENT OFFICE.

WALLACE B. VAN ARSDEL, OF BERLIN, NEW I IAMPSHIRE, ASSIGNOR '10 BROWN COMPANY, OF BER-LIN, NEW HAMPSHIRE, A CORPORATION OF MAINE.

APPARATUS FOR REGULATING GAS FLOW.

Original application filed November 10, 1921, Serial No. 514,191. Divided and this application filed December 16, 1925.

This invention relates to means for providing resistance to the flow of gases in apparatus for the production of nitrogen by the combustion of hydrogen in air and the removal of the products of combustion from the residual gas, and is divided from the subject matter of application Serial No. 514,191, filed November 10, 1921.

More particularly this invention is concerned with means for supplying a constant and regulable amount of air and hydrogen to a combustion furnace, and safety devices for minimizing the danger of explosions or of producing a gas which either forms an explosive mixture with air or contains an excess of air. These and other features of the invention will appear from a more complete description of an illustrative embodiment thereof disclosed in the accompanying drawings in which Figure 1 is a diagrammatic view of the ap paratus.

The flow of a gas in practice is always regulated by making use of a drop in pressure across some sort of resistance, an increase in flow being accomplished by either lowering the resistance while keeping the pressure difference constant or increasing the pressure difference while the resistance is held constant, or by combinations of the two methods.

In the present instance as the air and hydrogen are mixed in the combustion furnace the outlet pressures of the gases are equal, though variable dependent on the use to be made of 335 the gas. As it is quite important that the ratio of the hydrogen to the air shall be kept constant so as to permit complete combustion without undue excess of either hydrogen or air in the final product, it is essential that the initial pressures and the resistances be closely regulated. As the final pressure may vary somewhat, as before stated, it therefore becomes important that the initial pressure shall be somewhat high and the resistances large to cause the drop in pressure to be considerable in order that slight variations in the final pressure may have an inconsiderable elfect on the total drop. It is also essential that the initial pressures be held closely constant. In order to so hold these initial pres- Serial No. 75,805.

sures, weighted gasometers have been em ployed, since it is evident that pumps alone will not give sufficiently constant pressure. In order that the resistances may be considerable to effect a marked decrease in pressure and yet be dependable, a long series of pipes of greater than capillary diameter are employed. These pipes should be of material not substantially corroded by any of the constituents of the gas, brass having been found satisfactory in practice. Resistances to the flow of gases are often composed of constrictions or orifices, in the line. Such constrictions to accomplish the large decrease in pressure here desired would need to be of an extreme type, the orifice being merely a pin hole, or the constriction a capillary. As such constrictions are liable to change in resistance owing to corrosion or sudden complete plugging by a comparatively small particle of solid material, they are evidently not suited to the present purposes.

Referring then to Figure 1 the apparatus comprises a pair of air and hydrogen pumps shown at 1 and 2 both of which are belt connected to a driving motor 3. From each pump the gas passes through a cooling tank 1 for condensing out moisture and then through a separator 5 in the air line and a similar separator 6 in the hydrogen line, preferably of the bafile type, to remove suspended droplets of moisture. From there the gases pass through the bag filters 7 and 8 to remove particles of solid matter or oil which might be in suspension, and through regulating valves 9 and 10 to air and hydrogen gasometers 11 and 12. From the gasometer 11 the air passes through a system of pipes 18 form ing the resistance element and through a pipe 14: to the combustion furnace at 15. The hydrogen passes from the gasometer 12 through the resistance piping 16 and the pipe 17 to the furnace. The size and length of the resistance piping are, of course, dependent on the capacity of the plant and the pressure drop desiredthe smaller the volume of gas required, the longer the piping of a given size, or the smaller the piping of a given length for equal pressure drop. Preferably piping about inch in diameter would be about the smallest size successful in order that capillary effects might not be noticeable.

The furnace 15 may be of any desired con-- struction suitable for mixing and binning the gases. In a preferred form the air and hydrogen may be suppliedto the furnace through concentric pipes 21 and 22, which are connected respectively to the air pipe 1% and the hydrogen pipe 17, the pipes 21 and 92 ter minating in a suitable comb stion nozzle (not shown). For convenience in lighting, the pipes 21 and :22 are connected by flexible tubing with the pipes i l and ii so that the comb tion nozzle may be withdrawn from the fur nace, a small plug cock as and 31 being provided in each line to adjust the qi-iantity of gas initially. On star-tin up after the gasometers are full and hydrogen has run from the nozzle until tests show it Free of oxygen, the hydrogen plug cool: is partly closed so that the gas may be safely 1 hl'cd, and the nozzle is then inserted in the furnace, the flanges bolted, and both plug cocks opened wide. This procedure eliminates the danger of an explosion in the furnace on starting the apoaratus.

The hot mixture of nitrogen and superheated water vapor in the furnace may then be cooled and the water removed so that the nitrogen may be utilized. This cooling and separating out of the water may be carried out, in stages, as shown in Figure 1, an air cooler 35 being first employed, then a water cooler 36, a separator 37 for removing the droplets of water, and finally, if desired, refrigerated brine in duplicate coolers 38, one of these coolers being operated while the incrustations of ice are removed from the other. At this point the gas may be tested and upon excess of either oxygen or hydrogen being shown adjustments may be made in the apparatus. It is found convenient to make preliminary rough adjustments in the resistances by varying the length of piping through which the gases flow. Fine adjustments are then determined by varying the weight applied to the gasometer bells, it being desirable to maintain these weights as nearly equal as possible to impart equal initial pressures, in view of the fact that the final pressures of the gr ses as they are mixed are equal. The resistance elements are preferably composed of a series of pipes joined at their ends by cross connections #10 which have removable plugs opposite the ends of the pipes so that access may be had by a cleaning rod in order that the interiors of the pipes may be periodically and readily cleaned.

The pressure which may be successfully applied to gases by means of gasometers is limited by the available height of the gasometer tank since this pressure is balanced by the head of the sealing liquid. It has been found in practice that pressure of two pounds is suf ficient in this apparatus, the gasometer bells being innnersed in non-aqueous liquid such as oil which not only serves to prevent admission of moistiu'e to the gas but also serves to lubricate the rollers carried by the gasometer bells and which engage the inner faces of the tanks. By this means the rollers are always kept in free runnin; Condition and failure of the gasonieters to rreely function is reduced to the minimum.

it is iilcsirable that the pumps shall be able to pump the at somewhat higher pressure into these gasometers, particularly in view of the resistances interposed in the shape of the apparatus for removing water, dust, and so forth. For this purpose the pumps be .csigned to operate at, say, four pounds per quare inch, it being preferable to provide .al'ety valves at the outlet side of these pumps in order to prevent an excess pressure being supplied. Such valves are indicated on if ig- 'ure 1 at 4h) and 46, the valve for the air line neferably exhausting into the atmosphere and the valve do for the hydrogen line preferably exhausting through the pipe 47 into the pump intake. This construction provides ample pressures of the gases while insuring against excessive pressures.

The pressures on the gases in the gasometers are regulated by weights which may be carried on the tops of the gasometer bells 50. These weights may be either of various sizes or may comprise a number of small weights so tl'iat by varying the weight on each gasometcr bell, the pressure on the gas within the gasometer can be finely adjusted.

it has been found that with an apparatus of this description supplies of gas may be fun nished to the furnaq sulliciently accurately to require little attention and to permit only slight changes in the constituents of the final gas.

While this apparatus has been described in connection with the production of nitrogen by the combustion of hydrogen in air, it is evident that means for regulating the flow of a plurality of any gases w iich itis necessary or deF-airable should take place in balanced ratio might employ features of this invention.

Having thus described an embodiment of this invention it should be evident that many changes and modifications might be made therein without departing from its spirit or scope defined by the appended claims.

I claim:

1. A method for establishing a substan tially proportional tlow of a plurality of gases which comprises passing each of said gases through a gasomcter to cause a substantially uniform initial. pressure thereon, and then passing the gases therefrom through a resistance substantially inversely proportional to the flow, each resistance comprising a subtant-ial length of piping of greater than capillarly diameter.

2. A method for establishing a substantially balanced proportional flow between a plurality of gases which comprises passing each of said gases through a gasometer to subject it to a substantially constant initial. pressure, and then through substantial lengths of piping of greater than capillary diameter to impart proportional resistances to the flow of the gases.

An apparatus of the class described comprising means for subjecting a plurality of gases to pressures of substantially constant value, means for mixing said gases, and resistances to the flow of the gases interposed between said pressure and mixing means to determine the proportion in which said gases shall be mixed, said resistances being of large value whereby the drop in pressure caused thereby is substantially greater than fluctuations in the pressure of the gases after they are mixed.

l. Means for causing substantially uniform flow of gas under substantially constant initial and final pressures which comprises means for removing solid and liquid impurities from said gas, a plurality of lengths of pipe of more than capillary diameter in single series arranged in substantial parallelism, said pipes being constructed of a material which is not substantially corroded by any of the constituents of the gas, cross fittings at the ends of said pipes, and plugs in said fittings opposite the ends of said lengths whereby on removal of said plugs a cleaning member may be passed therethrough.

5. A method of regulating the flow of gas from a gasometer through a resistance comprising a substantial length of pipe of greater than capillary diameter, which comprises effecting a rough adjustment by varying the length of said pipe, and effecting close adjustment by varying the weight applied to the bell of said. gasometer.

6. In a device of the class described, a mixing chamber through which gases may be caused to flow, apparatus for further treatment of the mixed gases connected to the chamber and offering to the flow of the gases a comparatively low resistance which may be subject to fluctuations, and means for maintaining a substantially constant proportional inflow of gases to be mixed into the chamber, said means comprising mechanism for supplying the gases at substantially equal and constant pressures and ducts for the gases offering to the flow of the gases constant proportional. resistances which are high compared with the resistance of the apparatus for further treatn'iel'it.

7. Apparatus for deliverying gas at a sub stantially uniform rate of flow, comprising means for supplying gas at a substantially uniform pressure which is high compared with the pressure at the point of delivery, in combination with a resistance device between said supply means and the point of delivery, said device comprising a plurality of lengths of pipe of more than capillary diameter, and fittings joining the ends of said pipes in single series.

8. Apparatus for delivering gas at a sub stantially uniform rate of flow, comprising means for supplying gas at a substantially uniform pressure which is high compared with the pressure at the point of delivery, in combination with a resistance device between said supply means and the point of delivery, said device comprising a plurality of lengths of pipe of more than. capillary diameter in single series arranged in substantial parallelism, cross fittings at the ends of said pipes, and plugs in said fittings opposite the ends of said lengths whereby on removal of said plugs a cleaning member may be passed through said lengths.

In testimony whereof I have afiixed my signature.

WALLACE B. VAN ARSDEL. 

